NADPH is an abbreviation of reduced form of nicotinamide adenine dinucleotide phosphate, which is a very important physiological substance present in all kinds of living cells, including human cells, and a co-factor for a number of enzymes that catalyze the oxidation-reduction reactions, and is referred to as reduced coenzyme II.
NADPH is involved in a variety of anabolic reactions, such as the lipid, fatty acid and nucleotide synthesis, in the living cells, in which NADPH is needed as a reducing agent and a hydrogen donor. In addition, NADPH not only serves as a carrier for hydrogen transfer, but also as a mediator for phosphoryl transfer and participates in a variety of synthetic reactions. Today, NADPH is widely used in the production of various kinds of products in pharmaceutical and biochemical enterprises. With the intensive study on NADPH in the area of treatment and prevention of diseases, NADPH becomes increasingly important as a health care product, and the market demand grows year by year.
At present, the methods for preparing NADPH mainly include 1. yeast fermentation; 2. chemical synthesis; and 3. biocatalysis. Chemical synthesis has the disadvantages of high cost and production of chiral compounds. The NADPH produced by yeast fermentation contains some organic solvent residue. Biocatalysis is the most environmentally-friendly pollution-free method for preparing NADPH, because no organic solvent residue and no problem of chirality are present and the prepared NADPH is an isoform of that existing in an organism.
In an existing method for preparing NADPH by biocatalysis, NADP is used as a substrate for preparing NADPH in the presence of a dehydrogenase. The crude NADPH product prepared through the method needs to be further purified to obtain a pure NADPH product. The purification methods commonly used at present include liquid chromatography and ion exchange resin method. Liquid chromatography has the advantages of high purity and high yield of the purified product. However, since NADPH has a functional group with strong polarity and hydrophilicity, an ion-pairing agent and a buffer salt are introduced in the process of purification by liquid chromatography. The ion-pairing agent is difficult to separate, and the use of an organic reagent is needed during the purification process, so liquid chromatography brings new impurities and has a high cost, and is thus not suitable for use in industrial production. By means of the ion exchange resin method generally used in the industry at present, the purity of NADPH obtained is only about 95% at most, and the yield is only about 60% at most. Therefore, the production capacity is greatly limited and cannot meet the market demand.